This application relates to a system for controlling delivery of a physiological fluid internally to a patient from a balloon catheter.
Balloon catheters may be used to deliver drugs to tissue at a desired location of a patient""s body, such as a blood vessel. Typically, the balloon catheter is positioned at the desired location for drug delivery from one or more distal drug delivery outlets, e.g., on the surface of the balloon or on the catheter shaft. The balloon is inflated through a balloon inflation conduit to block the flow of blood in the vessel, thereby enhancing local drug delivery. A stepper motor may be connected to an infusion syringe containing the drug to provide a continuous flow of drug during the procedure.
One aspect of the invention generally features a system for controlling delivery of a physiological fluid internally to a patient from a balloon catheter. The balloon catheter includes a distal balloon connected to a catheter shaft, an inflation-fluid conduit connecting the balloon to a proximal source of pressurized balloon inflation fluid, and a physiological-fluid conduit connecting a fluid-delivery outlet of the balloon catheter to a proximal source of pressurized physiological fluid.
The system includes a controller, an inflation-fluid pressurizer for maintaining inflation fluid in the inflation-fluid conduit under pressure, and a physiological-fluid pressurizer for maintaining physiological fluid in the physiological-fluid conduit under pressure. The inflation-fluid pressurizer is connected to receive signals from the controller to cycle pressure in the inflation-fluid conduit between a balloon inflating pressure and a balloon deflating pressure. The physiological-fluid pressurizer is connected to receive signals from the controller to cycle pressure in the physiological-fluid conduit between a fluid delivery pressure and a resting pressure.
The controller is programmed to synchronize signals to the inflation-fluid pressurizer with signals to the physiological-fluid pressurizer. Thus, periods of balloon inflating pressure in the inflation-fluid conduit generally overlap with periods of fluid delivery pressure in the physiological-fluid conduit, and periods of balloon deflating pressure in the inflation-fluid conduit generally overlap with periods of resting pressure in the physiological-fluid conduit.
In preferred embodiments, the system also includes a holder sized and shaped to hold both an inflation fluid delivery chamber having a first moveable wall and a physiological fluid delivery chamber having a second moveable wall. Movement of the first moveable wall changes the volume of the inflation fluid delivery chamber, and movement of the second moveable wall changes the volume of the physiological fluid delivery chamber.
The inflation-fluid pressurizer may have a first driver and a first connector sized and shaped for connection of the first driver to a first movable wall of an inflation fluid delivery chamber. The physiological-fluid pressurizer may have a second driver and a second connector sized and shaped for connection of the second driver to a second movable wall of a physiological fluid delivery chamber. The first driver may be connected to the controller via a first circuit, and the second driver is connected to the controller via a second circuit.
The first connector may be a push-pull coupling, so that the first driver can push the first moveable wall to decrease the volume of the inflation fluid delivery chamber and pull the first moveable wall to increase the volume of the inflation fluid delivery chamber. The second connector may be a push-only coupling, so that the second driver can push the second moveable wall to decrease the volume of the physiological fluid delivery chamber. The second driver cannot pull the second moveable wall to increase the volume of the physiological fluid delivery chamber, thus reducing the opportunity for undesired retrograde movement of bodily fluids into the physiological-fluid conduit.
The holder accommodates a first syringe with a plunger that moves the first movable wall. The push-pull coupling may include a flattened region of the plunger at least partially enveloped by a mating structure of the first driver. The movement of the first driver toward the inflation fluid delivery chamber thus pushes the plunger and moves the first moveable wall to decrease the volume of the inflation fluid delivery chamber, thereby increasing the pressure in the inflation-fluid conduit. The movement of the first driver away from the inflation fluid delivery chamber engages the plunger and moves the first moveable wall to increase the volume of the inflation fluid delivery chamber.
The holder may also accommodate a second syringe with a plunger that moves the second movable wall. The push-only coupling includes a flattened region of the plunger which mates with a flattened member of the second driver. The movement of the second driver toward the physiological fluid delivery chamber pushes the plunger and moves the second moveable wall to decrease the volume of the physiological fluid delivery chamber, thereby increasing the pressure in the physiological fluid delivery chamber. The movement of the second driver away from the physiological fluid delivery chamber disengages the flattened region of the plunger from the flattened structure of the second driver without changing the volume of the physiological fluid delivery chamber.
The first driver may include a first pneumatic cylinder that is independently controlled by a first solenoid relay. The first solenoid relay may be controlled by the controller. The second driver may include a second pneumatic cylinder that is independently controlled by a second solenoid relay. The second solenoid relay may be controlled by the controller, which includes a timer. The system may also include a housing that surrounds the holder.
Another aspect of the invention generally features a method for delivering a physiological fluid internally to a patient from a balloon catheter. The balloon catheter includes a distal balloon connected to a catheter shaft, an inflation-fluid conduit connecting the balloon to a proximal source of pressurized balloon inflation fluid, and a physiological-fluid conduit connecting a fluid-delivery outlet of the balloon catheter to a proximal source of pressurized physiological fluid.
The method uses a system comprising a controller, an inflation-fluid pressurizer for maintaining inflation fluid in the inflation-fluid conduit under pressure, and a physiological-fluid pressurizer for maintaining physiological fluid in the physiological-fluid conduit under pressure. The balloon is positioned at the internal location, and alternately inflated and deflated by cycling pressure in the inflation-fluid conduit between a balloon inflating pressure and a balloon deflating pressure. Physiological fluid is delivered to the internal location by cycling pressure in the physiological-fluid conduit between a fluid delivery pressure and a resting pressure. Pressure cycles in the inflation-fluid conduit are synchronized with pressure cycles in the physiological-fluid conduit. Thus, periods of balloon inflating pressure in the inflation-fluid conduit generally overlap with periods of fluid delivery pressure in the physiological-fluid conduit, and periods of balloon deflating pressure in the inflation-fluid conduit generally overlap with periods of resting pressure in the physiological-fluid conduit.
The physiological fluid may be a drug, such as thrombin, hirudin, hirulog, urokinase, low molecular weight heparin or other modified heparins, TPA, PPACK, 7E3, or any other antiplatelet, antiproliferative or antioxidant drug. The physiological fluid also may be any drug used in chemotherapy or any gene or gene construct used in gene therapy. The invention may be used to deliver drugs to locations in the vasculature, such as blood vessels or the heart. The invention also may be used to deliver drugs to body lumens, such as the alimentary tract, the reproductive system, the urinary tract or the biliary tree.
The invention increases the efficiency of irrigation of the tissue with the drug and, in some cases, may reduce the amount of time the flow of bodily fluid is interrupted. The invention also helps to eliminate the need for manual control of the balloon inflation and drug infusion so that the doctor may be free to monitor the procedure.
Other features and advantages will be apparent from the following drawings, description of the preferred embodiments and claims.